What nobody told you about moving abroad, is that life moves on, with or without you.

There’s the obvious milestones, like engagements and weddings and pregnancies. You knew you’d be missing these, and while you do your best to get home for as many celebrations as possible, you knew that at 30, you’d never be able to make them all. Not when you’re averaging 5 wedding invites a year.

But what really hits you in the gut is the more mundane. The casual posts by mutual friends after a boutique fitness class or at happy hour with the caption #bestfriends. The friends getting into crazy diets or workout routines, or training for marathons on Wednesday evenings with a newly discovered crew. Wednesday used to be your day. The friends who take vacations together, but not to visit you like they always promised they would.

The realization that you’ve been dropped from the group chat. No, of course it’s not relevant to you and sometimes it was a little annoying to get alerts for 100 messages, deciding which restaurant to go to for dinner, who wants to share a cab, and oh shit, did someone pick up my debit card at the bar?

Half the time you don’t reply, but it was comforting knowing that you were still in the loop. That you would be able to seamlessly integrate back in when you do return home. That you were still a part of the inside jokes and the bad date play by plays. That someday you could surprise your friends at their dinner, because you know exactly where they will be and at what time. You feel betrayed when they decide to move out of New York City, even though you moved out first.

Suddenly your friends not only have boyfriends and girlfriends you’ve never met, but now they are fiancées and spouses who you meet for the first time at the rehearsal dinner.

You may no longer be a bridesmaid, because in addition to being good friends, aren’t they also meant to be around to help organize wedding-related events? And how can you be expected to give a speech about a man or woman you’ve never met where you reflect on how your friend has become a better person because of their partner?

Or even to tell embarrassing stories about the string of bad Tinder dates they had before meeting the one they are sitting next to at the head table. Plus, are you really the best friends you used to be? Does a twice a week photo of a stranger touching himself on the subway or the label of some weird food you’ve discovered here (Mayochup) really count as staying in touch?

In all of your righteous indignance, sometimes you forget to look at it from their perspective; you left them. You made the choice to move abroad. You have made tons of new friends and gone on so many adventures and “eat, prayed and loved” your life… why shouldn’t they? And it’s great, because now you live abroad, you have friends from all over the world, you’ve expanded your cultural knowledge and sensitivities and you can understand more complex issues than you once did, with only your one-dimensional American perspective guiding you.

But what people don’t tell you is that moving abroad is like going off to college. Suddenly you find yourself in a strange environment, with no safety net or support system.

But so has everyone else. Bonding is fast, and it’s intense. There’s also approximately as much alcohol as there is your freshman year of college. There is oversharing and hooking up and fights about who you hooked up with and tearful makeups and lasting grudges and rumors and whispers. And just like the first semester of college, only a fraction of those relationships endure beyond the first six months.

These people don’t know you. They don’t know your family. They never met your grandmother who died 10 days after you arrived. They don’t understand the dynamics of your relationship with your siblings. They never met your ex. And of course there are also lifelong friendships that you do foster; people who do get to meet your family and hear about your grandmother and come to your apartment at 7am and help you put on pants when you pull your back out and you have no one else to call.

These are the people whose weddings you will attend 10 years from now, be it in Sri Lanka or London or Columbia. These are the special people without whom your life would never truly be complete.

But, as is inevitable with people in your line of work, regardless of how close you’ve become: they leave. The nature of your career is defined by temporary contracts, 3 month internship and practicum placements, “hardship postings” and rest and relaxation vacations.

People fly in for 12 weeks as part of a roving emergency response roster, or kill time in your stable country while waiting for a visa to visit the country in the midst of conflict to which they are assigned.

You meet someone when you first arrive who tells you that she doesn’t invest in getting to know someone staying less than 6 months. At first you are a little put off, but after two years, you find you apply the same rule. It’s too exhausting to invest the time to get to know someone and to truly be interested in that person and to open up to them about your hopes and fears and hilarious stories, all the while knowing that there is an expiration date on the friendship.

As predicted, back home, the “friendships that matter” endure, either through daily text messages, two hour facetime dates every couple of months, or the beautiful ability to not keep in touch for six months and then get together upon a visit home and not skipping a beat.

But at some point, you come home for a visit after six months, or a year, or two and find that you’re angry. Angry either because you’ve changed so much and everything else is still the same, or because people have changed, and you no longer fit into their lives the way you used to. In one scenario, you feel as if you are a totally different person because of all that you’ve experienced and you just want to grab your friend in a dead end job and dead end relationship by the shoulders and shake her and reminder her that she swore six months earlier that she would make some changes, yet here she is, waking up next to the same dead beat person, commuting to the dead end same job, and promising that she’ll make a change by Christmas.

On the other hand, you might come home to find that your friend has followed through, and has a new job and a new boyfriend and new friends and new passions and new inside jokes and “sorry, we’re doing a couples thing for New Year’s Eve, but let’s get drinks before you head back.” And you don’t begrudge her these plans, because you weren’t home for the last 3 NYEs, so why should she plan around you… but it doesn’t mean that it doesn’t hurt that you’ve been replaced.

And then a time comes when you just want to go home for good. Everyone you love from your home away from home has moved on, and the idea of picking up and moving somewhere new and starting this process all over again is overwhelming. But is it selfish to expect those at home to open you back into the fold with open arms, not feeling any resentment for the fact that you did leave, for two (or however many) years? Do they even have room for you in their lives anymore? Will they even be going to the bar for football Sundays now that they have a baby, or a marathon to train for, or the crew has drifted apart for the same reasons, or beer and wings on a Sunday is a recipe for disaster at Monday’s staff meeting, and now everyone pretty much just watches the game on the couch with their wives so that they can get to bed at a reasonable hour?

What nobody told you about moving abroad is that life moves on, with or without you. And you knew it would. But that doesn’t make it any less painful.